1. Technical Field
The present invention generally relates to antennas, such as external antennas used on wireless communication devices, and particularly relates to controlling antenna connectivity as a function of antenna orientation.
2. Background
Wireless communication devices, such as PC Cards, mobile terminals, etc., often make use of internal antennas and external antennas. For example, it may be convenient (or practically necessary) to include an internal antenna within a PC Card. Incorporation of the internal antenna makes the card more convenient to use in a laptop or other such system, and makes it more robust physically, as external antennas may be more prone to damage.
However, external antennas commonly offer better performance, e.g., greater gain or sensitivity, as compared to the internal counterparts. The reasons for these performance advantages are varied, but may include the ability to implement external antennas in a larger or more appropriate size, and the ability to space external antennas further away from parasitic coupling elements and active sources of interference.
While the mechanisms for detachably connecting external antennas to wireless communication devices are varied, a typical approach involves the use of complementary mating connectors on the device and the antenna. Known, non-limiting examples of such connectors include “SSMB” connectors, “MC Card Adapters,” “MMCX Adapters”, “MCX-Plug Adapters,” and “RP-MMCX Adapters.”
Whether or not these industry-standard connectors are used, a couple of features or characteristics are common to many types of (RF) mating connectors. First, the mating connectors included in the wireless communication devices may include or be associated with switching elements—e.g., spring fingers or other displaceable contacts—that actively connect an external antenna when it is plugged in and correspondingly disconnect the internal antenna(s). Conversely, such mating connectors reconnect the internal antenna(s) when the external antenna's mating connector is unplugged.
Another common characteristic is that the above types of mating connectors allow an external antenna to be rotated while it is plugged in. That characteristic actually is desirable in terms of reducing stresses on the mating connectors which is especially important with surface mount connectors and other potentially vulnerable mechanical/electrical configurations. However, external antenna rotation also can be problematic.
For example, the external antenna may offer performance improvements over the internal antenna only for a restricted range of orientations. In such cases, the external antenna's performance may degrade as it is rotated downward or otherwise away from its preferred angular orientation to the extent that its performance is inferior to the internal antenna. Other considerations, such as undesired antenna coupling, also may come into play with excessive rotation of the external antenna away from its preferred or nominal angular orientation.